We are well into the time of year where planning and execution of fieldwork must take cold stress into account. The purpose of this safety message is to provide a brief overview of cold stress-related requirements and provide a list of references for additional information.

APPLICABILITY – Stratus Define Practice CoW-049 spells out the requirements for heat and cold stress management during work activities.  If you have plans to work in a cold environment, please contact Dan or Jenn to further discuss the risks and control measures.

In summary, the evaluation of conditions and implementation of risk control measures for work performed outdoors is triggered by an unadjusted ambient air temperature of:

1. 50°F (10°C) or lower with damp conditions. Note: Damp conditions are “any work area condition that can compromise the dryness of the worker’s clothing”. They can range from saturated ground and vessel spray to precipitation ranging from a mist to rain, sleet, or snow;
2. 45°F (7.2°C) or lower, independent of dampness and location (indoor or outdoor).

MONITORING METHODS – Cold stress monitoring shall be performed using the following methods:

1. Ambient air temperature and wind speed shall be gauged and documented every hour to determine if the conditions have changed that require additional or different risk control measures;

2. Worker condition which consists in observing workers for signs of cold-related illnesses.

Note: Workers known to have personal conditions (heart disease, asthma, bronchitis, and diabetes…) or are taking medication that interferes with normal body temperature regulation shall not be allowed to perform work in conditions of 30°F (-1°C) or below.

MONITORING AND DOCUMENTATION – Monitoring must be performed at a minimum of hourly once the temperature/cold index thresholds above are reached. Monitoring results must be documented and cold stress training records will be maintained in the project file.

SAFETY TIP – Risk control measures include, at minimum:

1. Work/Warm Up Schedule: at minimum, one break every two hours that allows workers to retreat to a warm location (i.e. building, shelter, vehicle, etc.) for a minimum of ten minutes;
2. Cold Weather Safe Work Practices on dress wear, hydration, break schedules, buddy system, symptoms of stress and fatigue;
3. Special Considerations for Equivalent Chill Temperatures (ECT): Ambient air temperature and wind speed (velocity) influence the development of cold stress. Wind chill or Equivalent Chill Temperature (ECT) is the combined cooling effect of temperature and wind speed on exposed skin. Additional risk control measures are required when the ECT is equal to or lower than 20°F (-7°C) and again when the ECT is equal or lower than 10°F (-12°C).